Modelling of accretion and differentiation of the proto-Earth and its building blocks

拟议的项目将解决关于行星胚胎（地球的基石）的热、结构和成分（包括挥发物）进化的核心问题，在一系列巨大撞击之前的原始地球的积累，以及它的分化。将研究影响熔体离析和分化成层状结构的化学和物理过程，从而对这些过程有更全面的了解。申请人先前开发了一个适用于半径小于~500公里的天体的行星胚胎模型，该模型将进一步扩展，以考虑撞击加热和固态对流过程的热传输，而不是更适用于半径增加的天体。这种胚胎的生长及其分化将被考虑，从而产生火星大小的原始地球。该模型的另一个重要改进是确定熔融和结晶产物，以获得对行星胚胎成分分层的更好约束。虽然我们将侧重于数值模拟，但基于样品的地外物质（例如HEDs （howardite, eucrite, diogenite）和岩浆铁陨石）的地球化学矿物学数据以及任务结果的综合（例如Dawn任务）将用于指导和测试模型。

The proposed project will address the central questions regarding the thermal, structural and compositional (including volatiles) evolution of planetary embryos (building blocks of the Earth), the accretion of the proto-Earth prior to the series of giant impacts, as well as its differentiation. Chemical and physical processes influencing the melt segregation and differentiation into a layered structure will be studied resulting in a more comprehensive understanding of these processes. A model of a planetary embryo for bodies smaller than ~500 km in radius was developed previously by the applicant and will be expanded to further consider impact heating and heat transport by solid state convection - processes than become more relevant for bodies with increasing radius. Growth of such an embryo and its differentiation will be considered, resulting in a Mars-sized proto-Earth. A further important enhancement of the model is the determination of the melting and crystallisation products to obtain better constraints on the compositional layering of planetary embryos. Although we will focus on numerical modelling, sample-based geochemical-mineralogical data for extra-terrestrial materials (e.g. HEDs (howardite, eucrite, diogenite) and magmatic iron meteorites) as well as synthesis of mission results (e.g. the Dawn mission) will be used to guide and to test the models.